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Lin JH, Li PC, Tang ST, Liu PT, Young ST. Industrial wideband noise reduction for hearing aids using a headset with adaptive-feedback active noise cancellation. Med Biol Eng Comput 2005; 43:739-45. [PMID: 16594300 DOI: 10.1007/bf02430951] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
High-intensity noises are a health hazard for industrial workers, and hearing protection is necessary to prevent hearing loss. Passive methods, such as ear muffs, are ineffective against low-frequency noise. Moreover, many hearing-impaired workers must wear hearing aids to enable communication at their workplace, and such aids can amplify ambient noise. To overcome this problem, the present study developed a headset equipped with a digital signal processing system to implement adaptive-feedback active noise cancellation (AFANC) to reduce low-frequency noise. The proposed AFANC headset was effective against wideband industrial noise, with a maximum noise spectrum power reduction of 30 dB. Furthermore, when used with a hearing aid, it improved the speech signal-to-noise ratio by up to 14 dB. These results suggest that a headset with AFANC would be useful for hearing protection in workplaces with high levels of low-frequency industrial noise, especially for hearing-impaired workers.
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Affiliation(s)
- J H Lin
- Institute of Biomedical Engineering, National Yang-Ming University, Taipei, China
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3
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Abstract
This study investigated the effects of noise on typical transient-evoked oto-acoustic emission (TEOAE) pass/fail criteria. Different levels of synthesised noise were added to one TEOAE signal, to determine the relationship between the signal-to-noise ratio (SNR) and typical TEOAE parameters: reproducibility, TEOAE level and corrected TEOAE level. Results showed that, with the same TEOAE signal, if the SNR decreased from 19 dB to -7 dB, the means of estimated reproducibility decreased from 97% to 7%, and the means of estimated TEOAE levels were doubled. Only the means of estimated corrected TEOAE levels were relatively insensitive to SNR. The standard deviations of all TEOAE parameter estimators increased with decreasing SNR. With these results, this study proposed that each typical TEOAE parameter alone should not be taken as the absolute pass/fail criterion. A combination of the corrected TEOAE level and the reproducibility would be better.
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Affiliation(s)
- L P Yang
- Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
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Yang LP, Young ST, Ku TS. Modification of the wavelet method used in transiently evoked otoacoustic emission pass/fail criterion to increase its accuracy. Med Biol Eng Comput 2002; 40:34-40. [PMID: 11954706 DOI: 10.1007/bf02347693] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Transiently evoked otoacoustic emissions (TEOAEs) are widely used in newborn hearing screening programmes for early detection of hearing losses. To increase the accuracy of a TEOAE pass/fail criterion that uses the wavelet method, it was demonstrated that the large estimation variance is a possible reason for the inaccuracy, and a modified wavelet method is proposed to solve the inaccuracy problem. In the modified wavelet method, N paired buffers, instead of only one, were used to store the total 512 subaveraged responses, and then the average of the calculated N cross-correlation coefficients between N pairs of TEOAE signals was taken in the pass/fail criterion. Four sets of 256 synthesised noise and eight sets of 256 synthesised noisy TEOAE signals were tested, and each set was tested 1,000 times. The results showed that the standard deviation of the correlation estimation was greatly reduced by using this average value with N selected as 4. As a result, the total number of single-scale cross-correlation coefficients below 50% decreased from 1281 to 195 for noisy TEOAE signals, and the total number of single-scale cross-correlation coefficients above 50% decreased from 90 to 0 for synthesised noise.
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Affiliation(s)
- L P Yang
- Department of Electrical Engineering, National Taiwan University, Taipei, Republic of China
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5
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Lin SL, Young ST, Liu CP, Chaing HT. Color encoding of the two-dimensional echocardiograms to analyze the echo texture of thickened mitral leaflets. SCAND CARDIOVASC J 2001; 35:326-34. [PMID: 11771824 DOI: 10.1080/140174301317116307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
OBJECTIVE The visual identification of different brightness of two-dimensional echocardiograms has natural limitations. The aim of this study was to perform a color-encoding technique on the echocardiograms and to evaluate whether the thickened mitral valve due to different etiologies may exhibit different colors and textures. DESIGN Two-dimensional echocardiograms in parasternal long axis view in late diastole were digitized in 28 patients with thickened mitral valves and 14 age-matched control subjects. These 28 patients included 14 patients with mitral valve prolapse (MVP) and 14 patients with rheumatic change of mitral valve (RMV). The mean gray level of the anterior mitral valve and the skewness of the histogram of gray level distribution of the anterior mitral valve were studied in all cases. RESULTS A significantly greater mean gray level of mitral valves in patients with RMV (114 +/- 20, p < 0.001) and lesser mean gray level in patients with MVP (49 +/- 12, p = 0.041) compared to that of control subjects (62 +/- 18) were noted. The mitral valves of the echocardiograms of patients with MVP tended to show a blue-to-green color, while those of RMV tended to show a yellow-to-orange color by this image processing system. Significant differences in skewness of the gray level distribution of mitral valves in control vs RMV (p = 0.001), control vs MVP (p = 0.005), and RMV vs MVP (p < 0.001) were also found. CONCLUSION This study demonstrates that the thickened mitral valves due to MVP and RMV may exhibit different colors and textures. Digital image processing can provide additional information to conventional echocardiograms in characterizing different echo textures of the heart valves.
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Affiliation(s)
- S L Lin
- Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung City, Taiwan, Republic of China.
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6
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Abstract
Using a homemade electrogastrography (EGG) system, we studied the characteristics of myoelectrical rhythm in gastric cancer (GC) patients. Based on a short-term Fourier transform, recorded slow waves could be automatically analyzed to obtain the following parameters: dominant frequency/power, percent of normal rhythm (2.4-3.7 cpm), power ratio, etc. Fifty histologically confirmed GC patients (34 men, 16 women) were enrolled before surgical intervention to measure their fasting and postprandial EGG parameters for 30 min. The cancerous parameters of GC patients were then obtained postoperatively. In addition, 46 healthy subjects were enrolled for comparison. When compared to controls, GC patients had the following characteristics: absence of postprandial increase in dominant frequency (GC: 3.04 +/- 0.47 vs 3.07 +/- 0.44 cpm, NS; controls: 3.02 +/- 0.31 vs 3.21 +/- 0.25 cpm, P < 0.001), marked power response after meal (P < 0.05), and obvious power ratio (4.58 +/- 7.38 vs 2.27 +/- 2.05, P < 0.05). Multivariate analysis indicated that advanced GC was the factor responsible for the obvious dominant power enhancement after meal (P < 0.05). Other demographic, clinical, and cancerous factors did not influence EGG parameters. We conclude that apparent arrhythmia is not encountered in GC patients, although they mainly exhibit obvious postprandial power response. Advanced GC is likely responsible for this power enhancement on EGG recording.
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Affiliation(s)
- F Y Chang
- Division of Gastroenterology, Taipei Veterans General Hospital and School of Medicine, National Yang Ming University, Taiwan
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Yancy CW, Fowler MB, Colucci WS, Gilbert EM, Bristow MR, Cohn JN, Lukas MA, Young ST, Packer M. Race and the response to adrenergic blockade with carvedilol in patients with chronic heart failure. N Engl J Med 2001; 344:1358-65. [PMID: 11333992 DOI: 10.1056/nejm200105033441803] [Citation(s) in RCA: 229] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND The benefits of angiotensin-converting-enzyme inhibitors and beta-blockers may be smaller in black patients than in patients of other races, but it is unknown whether race influences the response to carvedilol in patients with chronic heart failure. METHODS In the U.S. Carvedilol Heart Failure Trials Program, 217 black and 877 nonblack patients (in New York Heart Association class II, III, or IV and with a left ventricular ejection fraction of no more than 0.35) were randomly assigned to receive placebo or carvedilol (at doses of 6.25 to 50 mg twice daily) for up to 15 months. The effects of carvedilol on ejection fraction, clinical status, and major clinical events were retrospectively compared between black and nonblack patients. RESULTS As compared with placebo, carvedilol lowered the risk of death from any cause or hospitalization for any reason by 48 percent in black patients and by 30 percent in nonblack patients. Carvedilol reduced the risk of worsening heart failure (heart failure leading to death, hospitalization, or a sustained increase in medication) by 54 percent in black patients and by 51 percent in nonblack patients. The ratios of the relative risks associated with carvedilol for these two outcome variables in black as compared with nonblack patients were 0.74 (95 percent confidence interval, 0.42 to 1.34) and 0.94 (95 percent confidence interval, 0.43 to 2.05), respectively. Carvedilol also improved functional class, ejection fraction, and the patients' and physicians' global assessments in both the black patients and the nonblack patients. For all these measures of outcome and clinical status, carvedilol was superior to placebo within each racial cohort (P<0.05 in all analyses), and there was no significant interaction between race and treatment (P> 0.05 in all analyses). CONCLUSIONS The benefit of carvedilol was apparent and of similar magnitude in both black and nonblack patients with heart failure.
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Affiliation(s)
- C W Yancy
- University of Texas Southwestern Medical Center, Dallas 75390-9047, USA.
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Fowler MB, Vera-Llonch M, Oster G, Bristow MR, Cohn JN, Colucci WS, Gilbert EM, Lukas MA, Lacey MJ, Richner R, Young ST, Packer M. Influence of carvedilol on hospitalizations in heart failure: incidence, resource utilization and costs. U.S. Carvedilol Heart Failure Study Group. J Am Coll Cardiol 2001; 37:1692-9. [PMID: 11345386 DOI: 10.1016/s0735-1097(01)01190-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
BACKGROUND Carvedilol reduces disease progression in heart failure, but to our knowledge, its effects on hospitalizations and costs have not been evaluated. OBJECTIVES We examined the effects on hospitalization frequency and costs in the U.S. Carvedilol Heart Failure Trials Program. This program consisted of four concurrent, multicenter, double-blind, placebo-controlled studies involving 1,094 patients with New York Heart Association class II to IV heart failure, which treated patients with placebo or carvedilol for up to 15 months (median, 6.5 months). METHODS Detailed resource utilization data were collected for all hospitalizations occurring between randomization and the end of follow-up. In-patient care costs were estimated based on observed levels of resource use. RESULTS Compared with placebo, carvedilol reduced the risk of hospitalization for any reason by 29% (p = 0.009), cardiovascular hospitalizations by 28% (p = 0.034) and heart failure hospitalizations by 38% (p = 0.041). Carvedilol also decreased the mean number of hospitalizations per patient (for cardiovascular reasons 30% [p = 0.02], for heart failure 53% [p = 0.03]). Among hospitalized patients, carvedilol reduced severity of illness during hospital admission, as reflected by shorter length of stay and less frequent use of intensive care. For heart failure hospital admissions, carvedilol decreased mean length of stay by 37% (p = 0.03) and mean number of intensive care unit/coronary care unit days by 83% (p = 0.001), with similar effects on cardiovascular admissions. As a result, estimated inpatient care costs with carvedilol were 57% lower for cardiovascular admissions (p = 0.016) and 81% lower for heart failure admissions (p = 0.022). CONCLUSIONS Carvedilol added to angiotensin-converting enzyme inhibition reduces hospitalization risk as well as severity of illness and resource utilization during admission in patients with chronic heart failure.
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Affiliation(s)
- M B Fowler
- Division of Cardiovascular Medicine, Stanford University Medical Center, Palo Alto, California, USA.
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Chang FY, Lu CL, Chen CY, Lee SD, Young ST, Wu HC, Kuo TS. Real-time display of the stomach slow wave and its parameters in a newly designed electrogastrographic system. J Gastroenterol 2001; 36:10-7. [PMID: 11211205 DOI: 10.1007/s005350170148] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We designed a new three-channel electrogastrographic (EGG) system, which was easily operated on the Windows 95 platform and could automatically provide slow wave parameters. The purpose of the present study was to test its reliability and accuracy in clinical recording. The system included a signal acquisition device assembled on a printed circuit board. Recorded myoelectrical signals were filtered, amplified, digitized, and transmitted via this device into a notebook personal computer (PC). Based on the short-term Fourier transform the software could transfer the time domain of the signal into the frequency domain. Real-time displayed slow wave parameters, including dominant frequency/power, percent of normal frequency (2-4 cpm), instability coefficient in frequency/power, and power ratio, were automatically renewed every 64s. Twenty healthy subjects (M/F, 12/8; age, 23-51 years) were enrolled to measure both fast and postprandial myoelectrical activities for each 30-min recording. Our results indicated that meal ingestion significantly increased dominant frequency (3.15+/-0.20 vs 3.23+/-0.23 cpm; P < 0.05) and power (26.1+/-3.8 vs 28.4+/-3.9 dB; P < 0.05). The power ratio of the meal effect was 2.02+/-2.07. Other parameters, including instability coefficient and percent of normal frequency, remained similar despite food ingestion. This newly designed EGG system is acceptable for clinically measuring gastric myoelectrical activity; the real-time display of many EGG parameters is an advantage with this new system.
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Affiliation(s)
- F Y Chang
- Division of Gastroenterology, Taipei Veterans General Hospital, Taiwan
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Lin CL, Bai BR, Du LC, Hu CT, Young ST, Kuo TS. A novel speech controller for radio amateurs with a vision impairment. IEEE Trans Rehabil Eng 2000; 8:89-93. [PMID: 10779112 DOI: 10.1109/86.830953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This paper describes a portable speech controller system for persons with a vision impairment to adjust the channel frequency of a radio set via speech commands. The speech commands are recognized on a general-purpose digital signal processor using a hidden Markov model (HMM), and are used to remotely control radio channel changes.
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Affiliation(s)
- C L Lin
- Department of Electrical Engineering, National Taiwan University, Taipei, ROC
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11
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Abstract
To overcome the limitation of the microscope field, the study proposed an autostage sperm tracing system (ASTS), which could trace a particular sperm for a long time and distance. The ASTS was constructed by assembling a commercial microscope, an image frame grabber, a personal computer, and a motorized stage. Its performance was tested by evaluating 6 semen samples and by comparing the evaluation with those of other semen evaluations. The ASTS broke through the limitation of the microscope field and traced a particular sperm as long as possible. It analyzed the sperm track and calculated the motility parameters, such as curvilinear velocity (Vcl), straight-line velocity (Vsl), and linearity (L(in)). The sperm quality was then evaluated in real time, and the user could decide to capture or abandon a particular sperm in the IVF The ASTS enables users to evaluate sperm progression for a long time and to have the global quality of a particular sperm in real time. Its open structure has the flexibility for micromanipulating a semen sample, and has the potential application associated with a modern IVF technique.
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Affiliation(s)
- Y L Kuo
- Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan
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Wang CY, Chen CT, Chiang CP, Young ST, Chow SN, Chiang HK. A probability-based multivariate statistical algorithm for autofluorescence spectroscopic identification of oral carcinogenesis. Photochem Photobiol 1999; 69:471-7. [PMID: 10212579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
A probability-based multivariate statistical algorithm combining partial least-squares (PLS) and logistic regression was developed to identify the development stages of oral cancer through analysis of autofluorescence spectra of oral tissues. Tissues were taken from a 7,12-dimethylbenz[a]anthracene-induced hamster buccal pouch carcinogenesis model. Analyses were conducted at various excitation wavelengths, ranging from 280 nm to 400 nm in 20 nm increments, to assess classification performance at different excitations. For each excitation the PLS analysis and logistic regression were combined, on the basis of cross validation, to calculate the posterior probabilities of samples belonging to four stages of cancer development: normal tissues, hyperplasia, dysplasia and early cancers and frankly invasive cancers. Results showed that the 320 nm excitation wavelength optimally classified the cancer development stages: the accuracy rates for identifying samples at that excitation were 91.7%, 83.3%, 66.7% and 83.3% for the four respective stages. The average accuracy rate was 81.3%. These results suggest that the algorithm described in this study might be useful for the detection of human oral cancers.
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Affiliation(s)
- C Y Wang
- Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan
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13
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Abstract
Many drugs act as sperm stimulants and are of clinical value for male infertility. Current research deals with the physiological mechanisms of sperm motility/sperm stimulation and how long the effect lasts. For such a study, long-term monitoring of sperm motility becomes essential for traditional semen evaluation. A new system was designed to deal with the microscopic images of semen. Its performance was evaluated by studying the effect of EDTA on sperm motility. EDTA increased sperm curvilinear velocity (Vcl) and straight-line velocity (Vsl) by 31 and 20%. EDTA also prolonged the duration of motility by 68 and 61%, respectively. However, EDTA had less effect on the linearity of forward progression (Lin). The proposed system can analyze semen and does well at monitoring sperm motility for short term and long term. It may be valuable to test the possible role of sperm stimulation for male infertility and assisted reproduction.
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Affiliation(s)
- Y L Kuo
- Institute of Biomedical Engineering, National Yang-Ming University, Department of Surgery, Veterans General Hospital-Taipei, Taiwan
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Lin CL, Wu HC, Liu TY, Lee MH, Kuo TS, Young ST. A portable monitor for fetal heart rate and uterine contraction. IEEE Eng Med Biol Mag 1997; 16:80-4. [PMID: 9399090 DOI: 10.1109/51.637121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- C L Lin
- Department of Electrical Engineering, National Taiwan University
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Affiliation(s)
- I W Wang
- Institute of Biomedical Engineering, National Yang-Ming University, Taipei
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16
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Cohn JN, Fowler MB, Bristow MR, Colucci WS, Gilbert EM, Kinhal V, Krueger SK, Lejemtel T, Narahara KA, Packer M, Young ST, Holcslaw TL, Lukas MA. Safety and efficacy of carvedilol in severe heart failure. The U.S. Carvedilol Heart Failure Study Group. J Card Fail 1997; 3:173-9. [PMID: 9330125 DOI: 10.1016/s1071-9164(97)90013-0] [Citation(s) in RCA: 153] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Many patients remain markedly symptomatic despite optimal current therapy for heart failure. Beta-blockers have often been viewed as contraindicated in this group because of their potential adverse short-term effects on cardiac function. METHODS AND RESULTS One hundred thirty-one patients with severe congestive heart failure were enrolled into a double-blind, placebo-controlled study of the vasodilating beta-blocker carvedilol. All patients had symptomatic, advanced heart failure while on standard triple therapy, as evidenced by a mean ejection fraction of 0.22, marked reduction in distance traveled in a 6-minute corridor walk test, and severe impairment in quality of life measured by the Minnesota Living With Heart Failure Questionnaire. After a 2-week, open-label test of 6.25 mg twice daily carvedilol, 105 patients were randomized (2:1) to receive either carvedilol (up to 25 mg twice daily, n = 70) or matching placebo (n = 35) for 6 months while background therapy with digoxin, diuretics, and an angiotensin-converting enzyme inhibitor remained constant. Ten patients (8%) did not complete the open-label period because of adverse events and 11.4% in both the carvedilol and placebo groups dropped out in the double-blind phase. The study was terminated early by the Data Safety and Monitoring Board and follow-up evaluation was therefore aborted before the projected number of patients and follow-up time was achieved. Quality of life, which was the primary endpoint, improved similarly in the carvedilol and placebo groups, whereas the global assessment by the physicians and the patient exhibited a better response to carvedilol (P < .05). Hospitalization and mortality rate were too low to evaluate a difference, and exercise time and New York Heart Association classification did not change significantly in response to the drug. Left ventricular ejection fraction rose significantly (+0.09) in the carvedilol group compared with the placebo group (+0.02, P = .004). CONCLUSION The beta-blocker carvedilol can be safely employed in patients with severe heart failure. Improved left ventricular function with a trend for some improvement in symptoms combined with the experience with the drug in the larger population of less severe patients in this multicenter trial suggests that carvedilol may have a favorable long-term effect in heart failure of diverse severity.
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Affiliation(s)
- J N Cohn
- Cardiovascular Division, University of Minnesota Medical School, Minneapolis 55455, USA
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Abstract
Integration of information has enabled expeditious operation in air transfer, banking, shopping, and stock brokerage, but not in healthcare. Existing health information systems (HIS) are concerned too much with departmental performance and charge billing, and neglect the end users--the patients and the physicians. The resultant HIS then has divergent operation to antagonize the physicians, and has fragmented data to the disadvantage of patients. Recognizing the problems and the trend of HIS, this study proposed and implemented a patient-centred and physician-oriented HIS in a Urology clinic. The proposed HIS had patient care as its core, and accurately coded the patient's diagnoses and therapy information. It also offered a friendly environment and complete function for the physician to administrate medical records and to provide healthcare services. The HIS had client/server structure and an open system to protect the hardware investment and the software implementation. It will be the key to success in complete hospital environments.
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Affiliation(s)
- S T Young
- National Yang-Ming University, Department of Surgery, Veterans General Hospital-Taipei, Taiwan, Republic of China
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Herring JC, Schmetz MA, Digan AB, Young ST, Kalloo NB. Renal medullary carcinoma: a recently described highly aggressive renal tumor in young black patients. J Urol 1997; 157:2246-7. [PMID: 9146631 DOI: 10.1016/s0022-5347(01)64734-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- J C Herring
- Department of Urology, National Naval Medical Center, Bethesda, Maryland, USA
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Colucci WS, Packer M, Bristow MR, Gilbert EM, Cohn JN, Fowler MB, Krueger SK, Hershberger R, Uretsky BF, Bowers JA, Sackner-Bernstein JD, Young ST, Holcslaw TL, Lukas MA. Carvedilol inhibits clinical progression in patients with mild symptoms of heart failure. US Carvedilol Heart Failure Study Group. Circulation 1996; 94:2800-6. [PMID: 8941105 DOI: 10.1161/01.cir.94.11.2800] [Citation(s) in RCA: 477] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND We tested the hypothesis that carvedilol inhibits clinical progression in patients with mildly symptomatic heart failure due to left ventricular (LV) systolic dysfunction. METHODS AND RESULTS Patients (n = 366) who had mildly symptomatic heart failure with an LV ejection fraction (LVEF) < or = 0.35, had minimal functional impairment (defined as the ability to walk 450 to 550 m on a 6-minute walk test), and were receiving optimal standard therapy, including ACE inhibitors, were randomized double-blind to carvedilol (n = 232) or placebo (n = 134) and followed up for 12 months. The primary end point was clinical progression, defined as death due to heart failure, hospitalization for heart failure, or a sustained increase in heart failure medications. Clinical progression of heart failure occurred in 21% of placebo patients and 11% of carvedilol patients, reflecting a 48% (P = .008) reduction in the primary end point of heart failure progression (relative risk, 0.52; CI, 0.32 to 0.85). This effect of carvedilol was not influenced by sex, age, race, cause of heart failure, or baseline LVEF. Carvedilol also significantly improved several secondary end points, including LVEF, heart failure score, NYHA functional class, and the physician and patient global assessments. Carvedilol reduced all-cause mortality but had no effects on the Minnesota Living With Heart Failure scale, the distance walked in 9 minutes on a self-powered treadmill, or cardiothoracic index. The drug was well tolerated. CONCLUSIONS Carvedilol, when added to standard therapy, including an ACE inhibitor, reduces clinical progression in patients who are only mildly symptomatic with well-compensated heart failure.
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Affiliation(s)
- W S Colucci
- Boston University School of Medicine, Mass, USA
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20
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Packer M, Colucci WS, Sackner-Bernstein JD, Liang CS, Goldscher DA, Freeman I, Kukin ML, Kinhal V, Udelson JE, Klapholz M, Gottlieb SS, Pearle D, Cody RJ, Gregory JJ, Kantrowitz NE, LeJemtel TH, Young ST, Lukas MA, Shusterman NH. Double-blind, placebo-controlled study of the effects of carvedilol in patients with moderate to severe heart failure. The PRECISE Trial. Prospective Randomized Evaluation of Carvedilol on Symptoms and Exercise. Circulation 1996; 94:2793-9. [PMID: 8941104 DOI: 10.1161/01.cir.94.11.2793] [Citation(s) in RCA: 429] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Carvedilol has improved the symptomatic status of patients with moderate to severe heart failure in single-center studies, but its clinical effects have not been evaluated in large, multicenter trials. METHODS AND RESULTS We enrolled 278 patients with moderate to severe heart failure (6-minute walk distance, 150 to 450 m) and a left ventricular ejection fraction < or = 0.35 at 31 centers. After an open-label, run-in period, each patient was randomly assigned (double-blind) to either placebo (n = 145) or carvedilol (n = 133; target dose, 25 to 50 mg BID) for 6 months, while background therapy with digoxin, diuretics, and an ACE inhibitor remained constant. Compared with placebo, patients in the carvedilol group had a greater frequency of symptomatic improvement and lower risk of clinical deterioration, as evaluated by changes in the NYHA functional class (P = .014) or by a global assessment of progress judged either by the patient (P = .002) or by the physician (P < .001). In addition, treatment with carvedilol was associated with a significant increase in ejection fraction (P < .001) and a significant decrease in the combined risk of morbidity and mortality (P = .029). In contrast, carvedilol therapy had little effect on indirect measures of patient benefit, including changes in exercise tolerance or quality-of-life scores. The effects of the drug were similar in patients with ischemic heart disease or idiopathic dilated cardiomyopathy as the cause of heart failure. CONCLUSIONS These findings indicate that, in addition to its favorable effects on survival, carvedilol produces important clinical benefits in patients with moderate to severe heart failure treated with digoxin, diuretics, and an ACE inhibitor.
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Affiliation(s)
- M Packer
- College of Physicians and Surgeons, Columbia University, New York, NY, USA
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Abstract
Pressure pumps are useful in cardiovascular studies and in the evaluation of many circulatory devices. Currently available pumps are, however, far from perfect in their methods of syncrhonization, flexibility, and frequency response. To overcome these disadvantages, this study reports the design of a new pressure pump based on a linear motor. The pump can accurately synchronize with an animal's heart beats by using a phase-lock loop (PLL) technique. It has great flexibility and the ability to generate both arbitrary pressure waves and pure sinusoidal waves. The pressure pump has a frequency response of up to 50 Hz which is suitable for cardiovascular studies on rats, rabbits, cats and dogs.
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Affiliation(s)
- S T Young
- Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan, ROC
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22
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Young ST, Paulson EK, Washington K, Gulliver DJ, Vredenburgh JJ, Baker ME. CT of the liver in patients with metastatic breast carcinoma treated by chemotherapy: findings simulating cirrhosis. AJR Am J Roentgenol 1994; 163:1385-8. [PMID: 7992734 DOI: 10.2214/ajr.163.6.7992734] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Although the hepatotoxic effects of systemic chemotherapy are well known, CT findings in the liver after systemic chemotherapy have received little attention in the literature. In some patients with breast carcinoma metastatic to the liver who have received chemotherapy, a morphologic pattern develops similar to that associated with cirrhosis. This pattern is characterized by a lobular hepatic contour, segmental volume loss, and enlargement of the caudate lobe. The purpose of this study was to describe the CT appearance of this pseudocirrhosis and to correlate it with pathologic findings. MATERIALS AND METHODS We reviewed 65 CT examinations of 22 patients with stage IV breast carcinoma with hepatic metastases, who were receiving systemic chemotherapy and for whom abdominal CT scans showed pseudocirrhosis. Nineteen of 22 patients had follow-up CT scans at intervals ranging from 1 to 15 months. Criteria for the diagnosis of pseudocirrhosis included a lobular hepatic contour, segmental volume loss, and enlargement of the caudate lobe. CT findings were correlated with pathologic findings in seven patients. RESULTS In all patients, CT scans showed retraction of the capsular surface of the liver (15 diffuse, seven focal) with a lobular margin, a finding also seen in advanced cirrhosis. The retraction occurred at the site of subjacent metastases. Findings evolved over 1-3 months. Six of seven patients had pathologic findings suggestive of nodular regenerative hyperplasia. No patients had pathologic evidence of cirrhosis. CONCLUSION In patients undergoing systemic chemotherapy for breast cancer metastatic to the liver, a pattern may develop that mimics the CT appearance of hepatic cirrhosis. Pathologic findings suggest nodular regenerative hyperplasia as a possible cause.
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Affiliation(s)
- S T Young
- Department of Radiology, Duke University Medical Center, Durham, NC 27710
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23
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Abstract
A much smaller percentage of thickened leaflets of the aortic valve have been found in the right or left coronary leaflet than in the noncoronary leaflet. This study investigated the pressure loading transferring to the leaflets of the aortic valve and their effects on the valvular thickening. A simple ascending aorta model was established, and a simulation was made. The pressure loading in the coronary and noncoronary leaflets then were estimated. The simulation results showed that 5.8% to 17.% percentage of pressure loading to the coronary leaflet may be decreased by the coronary perfusion in diastole. The coronary arteries play an important role on pressures in the sinuses of Valsalva. The smaller pressure loading transferring to the coronary leaflet than that to the noncoronary leaflet is one reasonable explanation related to the thickened leaflets of the aortic valve.
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Affiliation(s)
- S T Young
- National Yang-Ming University, Department of Surgery, Taipei, Taiwan, ROC
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24
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Young ST, Paulson EK, McCann RL, Baker ME. Appearance of oxidized cellulose (Surgicel) on postoperative CT scans: similarity to postoperative abscess. AJR Am J Roentgenol 1993; 160:275-7. [PMID: 8424333 DOI: 10.2214/ajr.160.2.8424333] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE Oxidized regenerated cellulose (Surgicel), a sterile knitted fabric that causes thrombus formation because of its physical properties, is frequently used for intraoperative hemostasis. Unlike traditional surgical sponges, it is bioabsorbable and can be left in the surgical bed. On CT scans, the appearance of the retained oxidized cellulose can mimic that of an abscess. The purpose of this study was to describe the appearance of oxidized regenerated cellulose on postoperative CT scans so that an erroneous diagnosis of an abscess can be avoided. MATERIALS AND METHODS We reviewed the CT examinations of five postoperative patients in whom oxidized regenerated cellulose had been used for surgical hemostasis. Operative reports and surgeons confirmed the use of oxidized cellulose. Four CT scans were abdominal examinations, and one was a head examination. RESULTS In four cases, CT scans showed focal, linear collections of gas within masses with mixed attenuation in or near the operative site. No air-fluid levels were present. In three patients, cultures of specimens obtained by aspiration were negative for pyogenic organisms. CONCLUSION Retained oxidized cellulose can mimic an abscess on CT scans. Focal collections of air centrally located within a mass should alert the radiologist that oxidized cellulose may have been placed in the operative site, and an appropriate history should be sought.
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Affiliation(s)
- S T Young
- Department of Radiology, Duke University Medical Center, Durham, NC 27710
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25
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Abstract
The frequency properties of arterial beds in organs were studied by temporarily ligating the renal, the gastric, the splenic or the superior mesenteric arteries of rats. Blood-pressure waves of the tail arteries were recorded before and during the ligations, and were analysed by Fourier's transformation. Their frequency spectra have been found to change profiles following specific patterns with the ligations of different arteries. The results were significant with regard to the frequency selectivities of the organic arterial beds. Such frequency properties can be clearly explained when the circulation system is viewed as an electrical circuit network in which the organic arterial beds work as filters.
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Affiliation(s)
- S T Young
- Institute of Biomedical Engineering, Yang-Ming Medical College, Taipei, Taiwan, Republic of China
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26
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Abstract
Laparoscopic nephrectomy was performed in 15 male pigs, the procedure was successful in 14. Extraction of the intact kidney through a 5-cm lower abdomen incision was done in 7 animals; complete destruction and evacuation of the kidney was accomplished by a round-knife suction device through a 1-cm port in another 7 pigs. Grossly, the specimen consisted of sausage-like tubular renal tissue and a small amount of tissue debris. Pathology revealed that the glomerular and tubular structures were well preserved, no interstitial hematoma could be found. Four ports were usually used, one 1-cm umbilical camera port, one 0.5-cm port for ureter traction, and two 1-cm working ports along the midclavicular line. All the pigs recovered uneventfully. The average operation time was 3 h 20 min. The application of endo-GIA (United States Surgical Corporation) for renal hilum reduced the operative time to 2 h 20 min. Complications included renal vein tear during endoclip application and cutting in the first case, mild subcutaneous emphysema in 2 cases. This first pig received exploratory laparotomy for the repair and ligation of the renal vein. No more major complications occurred with increasing experience. From this porcine experiment, we conclude that the combination of laparoscopy, a tissue destroyer and an endobag for the entrapment of kidney seem to be a promising technique for clinical nephrectomy.
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Affiliation(s)
- A W Chiu
- Department of Surgery, National Yang-Ming Medical College, Veterans General Hospital-Taipei, Taiwan, ROC
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27
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Abstract
Managers may desire an approach to combining multiple productivity measurements into one score. This article demonstrates two approaches to aggregating multiple measurements, data envelope analysis (DEA) and the Multicriteria Performance/Productivity Measurement Technique (MCP/PMT). These methods are applied to actual hospital materials management data and do not result in significantly different results. The productivity analysis must then be tempered according to managerial judgement.
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Affiliation(s)
- S T Young
- University of Utah, Graduate School of Business, Salt Lake City
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28
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Chang SC, Shieh DB, Young ST, Yip SW, Wong TT. [The tracing of brain tissue and 3-D imaging display CT image application: 3-D recursive tracing]. Zhonghua Yi Xue Za Zhi (Taipei) 1991; 48:376-81. [PMID: 1659938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The size and the shape of brain tissue offer lots of information for clinical diagnosis and treatment. The commercial imaging systems, such as x-ray computer tomography (CT) and magnetic resonant image (MRI), always display only two dimensional (2-D) image, which makes quantitative diagnosis of the variation of brain tissue very difficult. Furthermore, some tissue may be connected through little vessels, which is also difficult to identify using discrete 2-D image. In this study, we processed CT image data using an general purpose IBM personal computer. A new three dimensional (3-D) recursive tracing algorithm was proposed. This new algorithm can automatically extract the image of brain tissue in each 2-D image. The information obtained was therefore used to reconstruct 3-D image. This system allows user to observe 3-D size and shape of brain tissue from arbitrary view. Such 3-D image can also be used to calculate the volume of tissue. Using overlay projecting method, it can display skin, bone, brain tissue and gray material at the same time. Such display method accurately shows the relative position of each tissue and offer physicians important information for diagnosis and treatment.
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Affiliation(s)
- S C Chang
- Medical Department, National Yang-Ming Medical College
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30
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Abstract
The protooncogene c-fos produces a phosphoprotein, Fos, which regulates gene transcription processes. In neuronal systems, Fos has been proposed to couple synaptic transmission to changes in gene expression by acting in the cell nucleus in concert with other proteins to form complexes in the promoter regions of target genes. We report here that the acute administration of a single dose of the indirect-acting dopaminergic agonist cocaine increases multiple Fos proteins in rat caudate nucleus. The increase is dose-dependent and is apparent immunocytochemically at 1 hr, maximal at 2 hr, and absent 48 hr after treatment. The increase seen immunocytochemically is composed of several molecular weight species as assessed by Western blotting of proteins from isolated striatal cell nuclei. Administration of the specific dopaminergic receptor antagonists sulpiride and SCH-23390 prior to cocaine support a significant role for D1 but not for D2 receptors in mediating this effect. These data indicate that D1 dopamine receptors are linked to a cellular immediate-early gene system(s) and suggest an action of cocaine at one or more levels of gene expression via modulation of transcriptional processes in activated cells.
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Affiliation(s)
- S T Young
- Laboratory of Cerebral Metabolism, National Institutes of Mental Health, National Institutes of Health, Bethesda, MD 20892
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31
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Abstract
In order to investigate the effects of arterial beds on pressure waveforms in arteries, the pressure waves observed in the rat tail artery were resolved into their Fourier moduli before and during ligation of the left renal artery and the superior mesenteric artery. Consistently different patterns of waveform changes in the tail artery were seen on occlusion of these vessels. Ligation of the renal artery reduced, and of the superior mesenteric artery increased, the pressure harmonics over most of the spectra. These results imply that to study the changes in the pressure contours as the observation point is moved downstream, one may have to account separately for the contributions of individual arterial beds. This is relevant in considering the degree to which it is appropriate for data to be amalgamated in models of the systemic arterial bed.
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Affiliation(s)
- S T Young
- Department of Electrical Engineering, National Taiwan University Institute of Biomedical Engineering, Yang-Ming Medical College, Taipei, Taiwan, Republic of China
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32
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Abstract
Based on the difference in electrical conductivity between hyperplastic prostatic tissue and tissue of the surgical capsule, we have developed a monitoring computer that distinguishes the former from the latter. The computer sounds an alarm when the cutting loop of the resectoscope touches the capsule, followed by an automatic cut-off of the power source 0.4 s later; thus inadvertent perforation of the surgical capsule can be avoided in most cases. The function of the computer has been tested in 73 patients with benign prostatic hyperplasia. The results show that, with Nesbit's technique of transurethral resection, tiny perforations of the surgical capsule, usually 1 to 2 mm in diameter, occurred in all 30 patients operated on without computer monitoring, but only 3 of 73 computer-monitored patients had such an occurrence. There was a slight increase in the weight of resected prostatic tissue among the computer-monitored patients, but the difference between the time spent on the procedure between the two groups of patients was not significant. Apart from its monitoring function, the computer may reduce eye strain and mental stress in the surgeon, especially when resecting a large hyperplastic prostate.
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Affiliation(s)
- L S Chang
- Department of Surgery, National Yang-Ming Medical College, Taipei, Republic of China
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33
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Yeh TS, Tsai SK, Hung HL, Lee TY, Chen SR, Young ST, Kao T. Computerized feedback autoregulation of neuromuscular blockade. Ma Zui Xue Za Zhi 1988; 26:123-30. [PMID: 3185163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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34
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Young ST. Performance measurements for hospital materiel management. J Healthc Mater Manage 1988; 6:44, 46-7. [PMID: 10287654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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35
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Young ST, Chan KH, Chen CF. An instrument using variation of resistance to aid in needle tip insertion in epidural block in monkeys. Med Instrum 1987; 21:266-8. [PMID: 3119964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A new method is proposed to detect the entrance of a needle into the epidural space. Measuring the changes in electric resistance during the insertion of the needle through different tissues in the interspinal space can help anesthesiologists judge whether and when the needle has entered the epidural space. This preliminary, animal study showed that the proposed method performed quite satisfactorily. The electric resistance of the tissues in the interspinal space varied from 1.57 +/- 1.22 k omega to 2.93 +/- 1.14 k omega, and the resistance of the epidural space varied from 9.00 +/- 1.12 k omega to 14.64 +/- 1.25 k omega. The difference was statistically significant (p less than 0.001). This difference in the resistance can be used to verify placement of the tip of the needle in the epidural space and help anesthesiologists administer epidural anesthesia.
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Affiliation(s)
- S T Young
- Institute of Medical Engineering, National Yang-Ming Medical College, Taipei, Taiwan, ROC
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